A pilot study of the ultrathin cryoprobe in the diagnosis of peripheral pulmonary ground-glass opacity lesions

BACKGROUND: It is very difficult to obtain samples of peripheral pulmonary ground-glass opacity lesions (GGOs) by traditional transbronchial biopsy. This study was conducted to evaluate the diagnostic efficacy and safety of transbronchial cryobiopsy (TBCB) of GGOs using a newly developed ultrathin cryoprobe with an outer diameter of 1.1 mm. METHODS: We retrospectively analyzed 20 patients with 23 GGOs who underwent TBCB using the ultrathin cryoprobe from October 2018 to November 2019 in the Shanghai Chest Hospital. The TBCB procedure was performed under the guidance of virtual bronchoscopic navigation (VBN), electromagnetic navigation bronchoscopy (ENB), endobronchial ultrasound, and fluoroscopy. We collected the baseline information of participants, reported diagnostic yield and complications, and analyzed factors may have affected the diagnostic yield. RESULTS: A total of 23 GGOs (12 pure GGOs, 11 mixed GGOs), with an average diameter of 21.58±11.88 mm, underwent TBCB, and the diagnostic yield was 82.61% (19/23). Of the 19 GGOs diagnosed by TBCB, 12 were adenocarcinomas, 5 were inflammation, 1 was occupational interstitial lung disease, and 1 was a pulmonary meningothelial-like nodule. The remaining 4 undiagnosed lesions were confirmed to be adenocarcinomas by further analysis. The diagnostic yield was unchanged by factors including size (GGOs ≥20 mm, GGOs <20 mm), navigation (VBN, ENB), fluoroscopic visibility (visible, invisible), GGO-component (pure GGOs, mixed GGOs), and guide sheath (K-201, K203). There was no presentation of pneumothorax or severe hemorrhage. CONCLUSIONS: The ultrathin cryoprobe is feasible, safe, and has a high diagnostic yield in the diagnosis of pulmonary GGOs. There is vast potential for the ultrathin cryoprobe as a tool for the diagnosis of GGOs, especially for cases suspicious of early-stage lung cancer. TRIAL REGISTRATION: ClinicalTrials.gov. No: NCT03716284. Registered: 20 October, 2018. URL: ClinicalTrials.gov.